1. Field of the Invention
The present invention relates to an inflatable vehicle occupant protection device and, in particular, to an air bag module having a cover.
2. Description of the Prior Art
An inflatable vehicle occupant protection device is used in a vehicle to protect an occupant during an emergency situation. Such a device includes an air bag and an inflator for providing inflation fluid for inflating the air bag. The inflator and the air bag are attached to a reaction plate. A cover, which covers the air bag, is also attached to the reaction plate. When an emergency is sensed, a signal is transmitted to the inflator to actuate the inflator to inflate the air bag. During inflation of the air bag, the air bag ruptures the cover at a tear seam in the cover and expands into the vehicle occupant compartment. The inflated air bag acts as a cushioning device to prevent or reduce the force of the vehicle occupant""s impact with parts of the vehicle.
To protect an occupant during a collision, an air bag must inflate at a high rate of speed. The outward expansion of the air bag imparts a force toward the vehicle occupant. Methods are available to control this outward force. One such method includes folding the air bag in a manner causing the air bag to inflate initially primarily in a lateral direction and secondarily in an outward direction. Although the folding of the air bag limits the inflation force directed outwardly toward the occupant, the lateral force of the inflating air bag may tend to deform, and could rupture, the side panels of the cover. The deformation and possible rupturing of the side panels could affect the proper deployment of the air bag.
The present invention is an apparatus for helping to protect a vehicle occupant. The apparatus comprises an inflatable vehicle occupant protection device, an inflator, a cover, and a reaction plate. The inflator provides inflation fluid to inflate the inflatable device. The cover at least partially encloses the inflatable device and the inflator. The cover has a front panel, which faces a vehicle occupant, and side panels, which laterally surround the inflatable device. The reaction plate has a base plate portion to which the inflatable device, the inflator, and the cover are attached. The reaction plate has at least one projection extending from the base plate portion. The at least one projection overlies at least a portion of at least one of the side panels of the cover to resist deformation of the at least one side panel laterally away from the inflator as the inflatable device inflates.
A feature of the present invention is that the cover and the at least one projection have interlocking portions which become interlocked during relative movement of the cover toward the base plate portion during assembly. The interlocking portions help retain the cover and the reaction plate together.